QUANTUM-FIELD-THEORETICAL PROCESSES NEAR COSMIC STRINGS - TRANSITION-PROBABILITIES AND LOCALIZATION

We study mutually and self-interacting Klein-Gordon fields in cosmic-string spacetimes. The discussion is based on cylindrical particle modes, which are physically interpreted in referring to the corresponding distributions of classical particles. The relation to asymptotic plane-wave modes and the related quantum-field-theoretical particle states is given. The transition probabilities of tree-level processes are discussed in general for Minkowskian and non-Minkowskian processes. Exact expressions for the total transition probabilities are worked out. Based on the phenomenon of localized absence, it is possible to approximately localize the non-Minkowskian processes of mutual interaction to cylindrical effective interaction regions around the cosmic string.